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Many terrestrial mammalian migrations are disappearing before they are documented. The Boma-Jonglei ecosystem in South Sudan, one of the world's poorest and most conflicted countries, contains some of the largest, longest, and least studied ungulate migrations. A rapidly increasing human population, ongoing armed conflict, and looming oil development, however, threatens the migration of 800,000 white-eared kob ( Kobus kob leucotis) and 160,000 tiang ( Damaliscus lunatus tiang) in this system. To document these migrations and identify potential conflicts, we examined the movements of ungulates in the Boma-Jonglei ecosystem using data from 14 collared individuals (12 kob, 2 tiang). We identified two separate dry season ranges of kob; from each, kob initiated migration with the onset of the rainy season, and migrated to a shared rainy season range also shared by the tiang. The maximum straight-line distance between telemetry locations of kob (399 km) and tiang (298 km) on their dry and rainy season ranges indicated these migrations were among the longest in Africa. The kob range was 68,805 km, 29% of which was within national parks and 72% within leased oil concessions (54-83% of parks overlap with potential oil concessions). The range of the tiang (35,992 km) occurred almost entirely (> 99%) within land leased to oil companies. Because disruption or elimination of these migrations will inevitably lead to significant population reductions, maintenance of the migration routes we identified through additional protection measures are essential to conserve one of the largest ungulate aggregations in the world. [ABSTRACT FROM AUTHOR]

The synthesis and post-synthesis separation of nanoparticles that are polydispersed in size and shape is important due to their variety of applications. In the present study, it is demonstrated that the Magnolia kobus plant extract produces a diverse mixture of extracellular gold and silver nanocrystals with a majority of polydispersed spheres; however, there are a significant number of homogeneously sized triangles, pentagons, and hexagons. The gold and silver nanoparticles synthesized using the M. kobus plant extract can be separated using density gradient centrifugation in the size range of 52 ∼ 117 nm and 38 ∼ 61 nm, respectively. The average particle sizes increase with increases in the sucrose concentration of each layer. Relatively larger but long, thin plates of gold nanoparticles appear in the higher density sediments, whereas a larger proportion of smaller spheres featured in the lower density gradients. Similarly, silver nanospheres of different sizes are separated at different density gradients with smaller proportions of plates. [ABSTRACT FROM AUTHOR]

New antelope material from the Tatrot type locality of the Tatrot Formation, Upper Siwaliks, northern Pakistan, allows us to recognize four antelopes, i.e., Antilope intermedia sp. nov. Khan and Akhtar, Antilope subtorta Pilgrim, 1937, Antilope cervicapra (Linnaeus, 1758), and Kobus porrecticornis (Lydekker, 1878). Comparisons with A. cervicapra and A. subtorta suggest that A. intermedia sp. nov. is closely related to the black buck A. cervicapra. The new material from Tatrot confirms the idea that antelopes in the Upper Pliocene Tatrot Formation were rather diverse. [ABSTRACT FROM AUTHOR]

In group-forming prey species, theory assumes that individuals within groups should scan independently of one another, with vigilance sequences being relatively unpredictable, making interscan durations highly variable. We attempted to detect any divergence from randomness in the scanning process in three mammalian prey species phylogenetically and geographically separated and exposed to different levels of predation: waterbuck, Kobus ellipsiprymnus defassa, under a high observed predation risk, eastern grey kangaroo, Macropus giganteus, still experiencing occasional predation and European roe deer, Capreolus capreolus, under a very low natural predation risk. Our results revealed that the focal interscan duration increased when the duration of the preceding interscan increased, whatever the studied species and the predation risk that its individuals experienced, and decreased with the preceding scan duration in two species under, respectively, occasional and low predation risks. The exponential distribution was the tested model that fitted the observed distributions of interscan durations least well. We discuss what can trigger non-randomness in scanning, through a non-homogenous Poisson process, at both intra-individual and inter-individual levels, particularly with regard to previous studies that have demonstrated synchronisation of vigilance in such mammals. Our results suggest the need to reconsider any assumption of randomness in scanning in the basic model predicting form and frequency of scanning behaviour by prey species. [ABSTRACT FROM AUTHOR]

Focuses on populations of puku antelope Kobus vardoni scattered throughout eastern and central Africa. Percentage of the total population that is restricted to the Kilombero Valley, Tanzania; View that the Kilombero Valley is an area rich in agricultural potential and natural resources; How wildlife populations are high and the inner valley is a game controlled area, although this only provides limited protection; Results of aerial surveys during the 1989, 1994 and 1998 dry seasons regarding puku population; Where signs of human activity were highest, indicating intense pressure on `boundary-zone? habitats at the floodplain-woodland interface; How puku use `boundary-zone? habitats during the wet season when large areas of grassland are flooded; Potential threats to the puku population; Impact of licensed trophy hunting on puku; How illegal hunting represents a serious threat near human settlements during the wet season and in accessible parts of the floodplain during the dry season.

Although it is commonly presumed that many populations of large-herbivores are limited by food availability, supporting evidence is scarce. This hypothesis was investigated in a population of over 800,000 white-eared kob in the Boma National Park region of the southern Sudan. Food availability, body condition, and mortality rates of adults and calves were measured during the dry seasons of 1982 and 1983. Sampled age distributions from both the live population and carcasses were used to calculate age-specific rates of mortality. In 1982, food supplies during the dry season were augmented by substantial rainfall, which produced regrowth of grass in areas that ordinarily had little green forage. As a result, fat reserves declined little, and rates of adult mortality showed no increasing trend. Total adult mortality was 5%. In 1983, there was no rainfall during the dry season and food intake was insufficient to meet the estimated energy requirements of kob. As a result, fat reserves declined and adult mortality rates increased fourfold. Total adult mortality was 10% (equivalent to the recruitment rate of yearling into the population). Calf mortality during the dry season was similar in both years (50%), based on field estimates of mortality rates and calf/female ratios. Lactation throughout the dry season possibly provided a buffer for calves against variations in food availability. The age structure of the live population in 1983 suggests that a drought in 1980 reduced kob numbers by 40%. These results suggest that adult survival is influenced strongly by the availability of food during the dry season. However, the duration of the dry season also plays an important role. During the dry season, declining fat reserves make an increasing proportion of the population vulnerable to mortality. As a result, even moderate droughts may lead to substantial changes in population numbers. [ABSTRACT FROM AUTHOR]

In Lake Nakuru National Park, Kenya, some territorial male waterbuck tolerate an additional adult male on the territory, which shares in the defence of the territory and has a higher chance than an outsider to become a territory owner. [ABSTRACT FROM AUTHOR]